Multilevel magnetic nanodot arrays with out of plane anisotropy:: the role of intra-dot magnetostatic coupling

Intra-dot inter-layer magnetostatic coupling have been investigated in trilayers which consist of two [Co/Pt] multilayers with out-of-plane anisotropy and different coercivities separated by a thick Pt layer. For single domain nanodots, the strong intra-dot inter-layer magnetostatic interactions manifest as a shift of the soft layer hysteresis loop. The amplitude of this shift decreases when the size of the dots is increased and/or when the temperature is increased. Satisfactory agreement is found between calculations and experimental results.